Re: [PATCHv2 4/8] khugepaged: Drain LRU add pagevec after swapin

From: Zi Yan
Date: Mon Apr 06 2020 - 09:11:33 EST


On 3 Apr 2020, at 7:29, Kirill A. Shutemov wrote:

> External email: Use caution opening links or attachments
>
>
> __collapse_huge_page_isolate() may fail due to extra pin in the LRU add
> pagevec. It's petty common for swapin case: we swap in pages just to

s/petty/pretty

> fail due to the extra pin.
>
> Drain LRU add pagevec on sucessfull swapin.

s/sucessfull/successful

>
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
> ---
> mm/khugepaged.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/mm/khugepaged.c b/mm/khugepaged.c
> index fdc10ffde1ca..57ff287caf6b 100644
> --- a/mm/khugepaged.c
> +++ b/mm/khugepaged.c
> @@ -940,6 +940,11 @@ static bool __collapse_huge_page_swapin(struct mm_struct *mm,
> }
> vmf.pte--;
> pte_unmap(vmf.pte);
> +
> + /* Drain LRU add pagevec to remove extra pin on the swapped in pages */
> + if (swapped_in)
> + lru_add_drain();
> +
> trace_mm_collapse_huge_page_swapin(mm, swapped_in, referenced, 1);
> return true;
> }
> --
> 2.26.0


â
Best Regards,
Yan Zi

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